Stencil sheet and method of making same



1935. H. P. ELLIOTT STENCIL SHEET AND METHOD OF MAKING SAME Filed Oct. 27, 1933 P O T T N O R F INVENTOR HARMON R ELLIOTT BYM v 5E ATTORNEY Patented Feb. 12, 1935 UNITED STATES PATENT OFFICE 1,990,535 STENCIL SHEET AND IHETHOD OF MAKING SAME Harmon P. Elliott, Watertown, Mass, assignor to The Elliott Ad Machine Company, a corporation of Massachusetts Application October 27, 1933, Serial No. 695,511 22 Claims. (Cl. 4138.6)

This invention relates generally to stencil So far as the addressing machine business was sheets adapted for conversion into a stencil by concerned, however, the problem was left still impact thereon of type, or type plates, or by unsolved by the Hill patent.

l!) vention is designed to produce a stencil sheet of impressions have previously displaced such coatl chines employing card stencils. or roller, or sector, carrying liquid ink and oper- For a long period of time stencil sheets and ating under relatively high pressure, the entire card stencils made out 01' yoshino coated with a cellulo coating o b mes cha d and coagulated gelatine compound were successfully saturated with ink, and after about the fourth 20 documents are made, while employing relatively postcards come out each with a complete smudge light pressures to force paste ink through the oi ink on its face, instead of the desired clearly t5 stencil sheet, and in card form in addressing printedname and post ofllce address. This remachines where relatively high pressures are suits from the high platen pressure having driven applied by reciprocating platens, or rotating the liquid ink through all the pores of the uncut sectors or rollers to force liquid ink through the coating, as well as between the exposed yoshino stencil cards. fibres at the cut portions. Also, the cellulose These stencil blanks, whether in sheet or card coated panel is more delicate in structure than 30 the stencil by e posing practically uncoated panels are soon stretched by such treatment and 35 operations, and the rust caused on typewriting yoshino panel still triumphantly holds the ad- 40 in straight duplicating work, because of the enorstencilizing it. v mous number of little card stencils used in the I have discovered, however, and this is the sub- 45 former; but the problem 01' the production of a stance of the present invention, that if such celcoated paper stencil which could be out without lulose coated encil blank, whether in sheet or Feb. 17, 1925, developed the idea of substituting broken, prevent liquid ink from passing through a yoshino coating formed with a cellulose ester the panel after it has been applied to the face and tempering agents, in place of the prior cothereof even under the full pressure required in aguiated protein and tempering agents, and gave. the best addressing machine practice, but which 5 the answer so far as ordinary duplicating work V will be sumciently broken and in part removed to such panel face, so that the ink under such pressure will pass through such partially cut or broken areas to practically the same extent as though no such backing film had been applied, complete success can be achieved in the best addressing machine practice with such cellulose coated and shellac-backed card stencils which can still be easily cut or stencilized on the ordinary typewriting machine without previous moistening.

The present invention is the result of a discovery that a film of the character described in my Patent No. 1,937,751 dated Dec. 5, 1933 also containing coloring matter will, when applied to the back of a stencil blank made in accordance with the teachings of said Hill PatentNo. 1,526,- 982 primarily for the purpose of increasing the legibility of the stencil when subsequently out, also, and quite'unexpectedly, qualify such cellulose coated stencil for successful continued use with liquid ink in any of the standard stencil addressing machines.

By way of a more detail description of the preferred method of carrying out my invention I may proceed as follows: A bath is formed of any .suitable cellulose ester, such as cellulose nitrate or acetatedissolved in a suitable solvent, such as amyl acetate, the cellulose content of the solution running from 5 to 8%, and to this is added about 50% by weight of a suitable tempering agent such as castor oil or soya bean oil, and from 3 to 5% of a fatty substance such as lard or cottolene (all as described in said Hill patent). The yoshino sheets are then drawn across the surface of such bath and hung up to dry.

After such cellulose coating has set the coated sheet is similarly drawn again across the surface of a bath of vamish-like solution which when transferred to the surface of the cellulose coated yoshino and allowed to set will form a film thereon which while unbroken will be practically impervious to liquid printing ink, but areas of which will be so broken up by the impact of a type striking the other face of the sheet that small portions of such film will be forced away from the remainder thereof and caused to adhere to any backing surface on which the coated sheet is resting during such stencilizing operation.

I prefer to use for such film-forming bath shellac dissolved in alcohol or other volatile vehicle, though other varnish-like solutions might be substituted. Also a coal tar derivative held in solution or suspension by the alcohol may be added. If it be desired to give an orange color to such backing film to add to the legibility of the completed stencil in the manner described in my said Patent No. 1,937,751 lwdrochloride of benzene-met-toluylene-diaminine may be the coal tar derivative selected, and other coal tar dyes may be used to produceother colors. Also, if a more transparent, uncolored stencil is desired, the dye may be omitted. The essential point is that a backing film shall be applied to p .the cellulose-coated panel which shall be substantially impervious to liquid printing ink so long as it is undisturbed, but shall be capable of being broken away to a considerable extent by the typeproduced impact applied to the face of the panel in the stencilizing or cutting operation, so that the portions of the film remaining on the type compressed areas shall present no substantial obstacle to the passage of ink under pressure, through the stencil. That a considerable portion of the rum material subjected to type impact is thus removed is shown by the fact that when a coal tar dye is incorporated in the film, enough of it is transferred to any backing sheet by the stencilizing operation to clearly reproduce thereon the typed legend in the color of such dye.

Stencils made according to my invention may also, of course, be used with paste ink such as is now employed on standard stencil duplicating machines, but, so far as I am at present advised, better results in the appearance and legibility of the printed page, envelope or post card can be obtained with the use of liquid ink, and as such liquid ink dries more quickly and completely on the printed surface of whatever character, it consequently will not smudge nor rub off when subsequently handled. Liquid ink also will produce good printing on bond or glazed surface papers, while paper with a more absorbent or dead surface is usually required for good work when paste ink is employed.

The above suggested and other variations in the materials and methods of procedure may be employed in carrying out my invention so long as the principles of operation above outlined are retained and the desired results secured in substance, and the resulting stencil sheet or card is within any of the definitions of the appended claims. 1

Thus, fabric bases of suitable loose or open texture other than yoshino might also, of course, be substituted for the latter, when desired, for any special reason, but as at present advised, I believe that yoshino most generally meets the requirements for successful commercialembodiments of the present invention.

, Also, while the best results from the use of my invention are realized when the thin, liquid proof but relatively frangible film is applied to a "dry stencil having the cellulose base coating described in the above mentioned Hill patent, the said invention can also be applied with advantage to stencils having other coatings which remain permanently soft enough to permit their being stencilized or out at any time in a typewriting machine without previous moistening. As examples of such other dry stencils in the prior art I may mention those having a coating mixture of protein and oil described in U. S. patents to Richard Land No. 1,584,951, dated May 18, 1926, and Nos. 1,604,886 and 1,604,887, dated Oct. 26, 1926, and those having a casein base coating such as described in British Patent 5,717 of 1928, among others.

All of these and other dry stencils necessarily have base coatings which are relatively soft, as compared with the older coagulated protein, otherwise they could not be displaced while dry by the type blows. Consequently they are all necessarily more or less readily permeable to liquid ink applied under the pressures used in addressing machines, and are also somewhat permeable to such ink even when used in the,

ordinary stencil duplicating machine's producing only lighter degrees of pressure; and as a result paste ink now has to be employed with each and all of them. The application to any or all of these dry stencil sheets of the thin, liquid proof but sufiiciently frangible backing film deposited thereon by drawing the dry coated sheet over the surface of a bath of shellac dissolved in alcohol, and across the edge of the vessel containing such bath, overcomes this defect of permeability to liquid inks after said film has hardened, and renders the stencils subsequently cut therefrom usable with both liquid and paste inks, and in addressing machines.

' plication to the relatively It is clear, therefore, that the underlying novelty of my present invention involves the apsoft base coating of any practical dry stencil (i. e. one which can be stencilized by type blows while free from other than hygroscopic moisture), of a thin, liquid proof and relatively frangible film which can be broken away by the blow of the type sufiiciently to thereafter let the ink pass through the coated sheet at that point. The base coating or filling for the yoshino is thick because it soaks into and through the loose fibre thereof, while the shellac film is thin because it is applied by contact to the surface of such dry, and only slightly absorb ent base coating or filling.

In the preferred embodiment of my invention the stencil blank which isto be "cut to form the completed stencil has the construction shown and described in my hereinbefore noted Patent No. 1,937,751, except that a relatively soft base coating which can be cut by the type without previous moistening of the sheet is substituted for the older coagulated coating assumed in my said patent specification to be used, though not specifically described, nor specifically claimed.

In both cases, however, the base coating is preferably applied by drawing the yoshino sheet across the surface of the bath, as hereinbefore stated, and the result with the present invention will be the same as that specifically described in my said patent so far as concerns depositing a major portion of the coating material upon one face of the yoshino, said more heavily coated surface thereafter forming the face of the stencil when it is being cut, as well as when it is being used for printing. film of. frangible varnish (whether colored or not) will be applied to the back of the sheet or card, i. e. to the yoshino surface having the thinner layer of base coating.

A specimen card stencil made according to my present invention is shown in the accompanying T sheet of drawings in which Fig. l is a front view of such card stencil and Fig. 2 is a cross section on line 22 of Fig. l with the respective thicknesses of the various layers of materials greatly exaggerated both relatively and absolutely.

In said drawings 1 indicates generally the card frame having a welt-strip extending around its inner border, to the under side of which latter a panel of thin but heavily coated paper is cemented. 2 indicates generally the welt-strip, 3 a sheet of yoshino paper, 4 a heavy coating of easily displaceable material (such as the cellulose compound hereinbefore described) the major portion of which is on the upper surface of the yoshino, and 5 is the backing film of, inkproof varnish, such as shellac, which has been broken away more or less completely as indicated at 'I, I by type impact applied to areas 6, 6 of the coated yoshino, which areas have been rendered susceptible of penetration by ink as a result oflateral displacement of major portions of one coating 4 caused by such impact from above. The unbroken areas of the varnish film 5 retain their original impermeability by ink.

Having described my'invention, I claim:

1. As a new article of manufacture a stencil blank comprising a thin sheet of loose-fibered paper supporting a layer of relatively soft composition capable of being laterally displaced by type-produced impact to form a stencil while the coated sheet is free from other than hygroscopic moisture, the major portion of which .base coat- In both cases also the thin .impact of type thereon,

ing material is located on one side of the paper, and a film of material on the other and more thin- 1y coated surface of said sheet substantially impervious to liquid ink but capable of being broken away to a considerable extent by such type-produced impact.

2. An article such as defined in claim 1 in which said backing film comprises a coal tar derivative mixed with shellac.

3; An article such as defined in claim 1 in which said backing film comprises a coal tar derivative such as hydrochloride of benzene-metatoluylenediamine mixed with shellac.

4. As a new article of manufacture a stencil-.

sheet adapted for conversion into a. stencil by" the impact of type thereon, the same comprising'a basehaving a type-impressible coating including a cellulose compound and a tempering agent, and a backing film of material substantially impervious to ink'but capable of being broken away to a considerable extent by such type-produced impact applied to the face of the sheet.

5. An article such as defined-in claim 4 in which said backing film consists mainly of shellac.

6. As a new article of manufacture a stencilsheet adapted for conversion into a stencil by the impact of type thereon, the same comprising a base having a type-impressible coating including a cellulose compound, a tempering agent and a fatty material, and a backing film of varnish substantially impervious to ink when undisturbed but capable of being broken away to a considerable extent by such type-produced impact applied to the face of the sheet.

7. An article such as defined in claim 6 in which said varnish is mainly composed of shellac. 8. As a new article of manufacture, a stencilsheet adapted for conversion into a stencil by the the same comprising a base having a type-impressible coating including a cellulose compound, a tempering agent and a fatty material. and a backing film of material substantially impervious to ink but capable of being broken away to a considerable extent by such type-produced impact applied to the face of the sheet. 1

9. An article such as defined in claim 8 in which said tempering agent is castor oil and said backing film comprises coal tar derivative mixed with shellac.

10. An article such as defined in claim 1 in which said base comprises yoshino fabric.

11. An article such 'as defined in claim- 1 in which said base comprises yoshino fabric and said backing film comprises a varnish;

12. As a new article of manufacture a stencilsheet adapted for conversion into a stencil by the impact of type thereon, the same comprising an open, porous base having a coating including a compound of cellulose which is soluble in a volatile solvent and tempering material, and a backing film of material substantially impervious to ink but capable of being broken away -to a considerable extent by such type-produced impact applied to the face of the sheet.

13. An article such as defined in claim 12 in being broken away to a considerable extent by the sheet.

15. An article such as defined in claim 14 in which said film is mainly composed of shellac.

16. As a new article of manufacture a stencilsheet adapted for conversion into a stencil by the impact of type thereon, the same comprising an open-texture base having a coating including a cellulose ester and a tempering agent, and a backing film of material substantially impervious to ink but capable of being broken away to a considerable extent by such type produced impact applied to the face of the sheet.

1'7. An article such as defined in claim 16 in which said backing film comprises a coal tar derivative mixed with shellac.

18. As a new article of manufacture a stencilsheet adapted for'conversion into a stencil by the impact of type thereon, the same comprising an open-texture base having a coating including a cellulose ester in admixture with a tempering agent and a fatty material and a backing film of material substantially impervious to ink but capable of being broken away to a considerable extent by such type produced impact'applied to the face of the sheet.

' 19. An article such as defined in claim 18 in which said backing film comprises a coal tar derivative mixed with shellac.

20. The herein described method of producing a sheet adapted for conversion into a stencil by the impact of type upon one face thereof without such type-produced impact applied to the face of previous "moistening thereof, which comprises saturating a yoshino base with a coating solution including a cellulose compound and tempering material. allowing the same to set, applying to the other surface of such coated sheet a thin backing film of varnish and allowing such backing film to set.

21. In a stencil comprising a panel of loosefibred paper provided with a relatively soft base coating which is type-impressionable while free from other than hygroscopic moisture, the combination therewith of a film of material substantially impervious to liquid ink, but capable of being broken away to aconsiderable extent by type-produced impact, located on the back face of said stencil.

22. The herein described process of producing a stencil which comprises embedding a sheet of thin loose fibred paper in a layerof relatively soft composition which. after being freed from other than hygroscopic moisture. can still be displaced laterally by the impact of type-blows so as to substantially expose the paper fibre beneath, allowing the sheet to dry, applying to one surface of such dry sheet a film of material substantially impervious to liquid ink but capable of being broken out by such type-produced impact sufficiently topermit such ink to pass through the sheet at those points, and finally indenting by type impact against the other surface of said sheet, the legend to be stenciled.

HARMON P. ELLIO'I'I 

